Abstract
A variable stiffness composite optimization framework for wind turbine rotor blades is presented. The framework consists of a multi-fidelity approach for wind turbine rotor analysis, where both structural and aerodynamic constraints are considered during the optimization. The potential of twist coupled blades to regulate the power on stall controlled wind turbines is investigated by exploiting the characteristic of unbalanced laminates to induce twist coupling. A complete stiffness variation along the blade span is considered during the optimization, while using the cost of energy as the objective function. Results show that unbalanced laminates provide a greater capability (compared to balanced laminates) to reduce the cost of energy of stall controlled wind turbines by exploiting extention-twist and bend-twist coupling of composite blades.